Growth, structure and magnetism of ε-Fe2O3 in nanoparticle form

Abstract

We present a novel and easy synthetic path to prepare ε-Fe₂O₃ (∼90%) with a small portion of α-Fe₂O₃ nanoparticles embedded in an amorphous silica matrix. An exhaustive structural study reveals the higher relative concentration of the ε-phase, with an average particle size of 17 nm. Confocal Raman microscopy and X-ray absorption spectroscopy are presented as novel techniques to characterize the ε-polymorph. The magnetic properties have been studied in a wide range of temperatures (5–1000 K), detecting blocking effects (∼135 K), collapse effects (50–125 K), Morin (∼268 K) and Néel (∼505 K) transitions.